What term do historians use to describe the study of the political ,social, cultural, and economic setting surrounding a historical event in order to understand it more thoroughly?

the answer you are looking for is contextualization

Explanation:

nothing certain is known about what happened, but it seems that the country declined gradually, perhaps due to bad government, or, more likely, due to a series of bad harvests, which resulted in widespread and recurrent famine.

a.

congress passed laws allowing for free passage between states.